This request is for funds to purchase a Nikon Ti inverted microscope with widefield, total internal reflection fluorescence (TIRF) and confocal capabilities for live cell imaging. This instrument will be housed within the Center for Biologic Imaging (CBI) at the University of Pittsburgh School of Medicine. The mandate of this core facility is to provide access to a full range of light and electron optical, image analysis, and morphometric methods to all research groups within the University of Pittsburgh School of Medicine, and Medical Center. Confocal microscopy is an essential service provided by the center, and there are multiple point scanning single microscopes available to users. There are no multipoint (spinning disk or moving pinhole array) confocal or TIRF imaging microscopes in the core facility. There are instruments of this type in the PIs laboratory and elsewhere on campus, however these are not core equipment. The PI has been making some time available to users on his own microscopes whenever possible, though at the current time it is simply impossible to meet demand for live cell confocal and TIRF imaging using the few unused hours on the PIs own microscopes. Therefore the reasons for this application are to provide high speed live cell confocal and TIRF imaging to users of the CBI. It is important to recognize that the CBI has two applications in this competition for similar equipment. The other application, for a live cell confocal will be placed in the new imaging core (a CBI satellite) in the regional biocontainment facility and will only be used for imaging highly dangerous pathogens. Because of the extremely limited access to and specialized function of this other microscope, there is absolutely no redundancy between the two applications. Since the CBI commenced operations 17 years ago, it has become an integral part of the medical research community currently participating in research projects with more than 200 PHS funded groups within the medical area, as well as in PHS supported projects with investigators in other departments and at neighboring institutions. The device requested here is a critical component of the continued growth of this institutional facility.